Nucleation-Free Gap Fill ALD Process

ABSTRACT

Processing methods comprise forming a gap fill layer comprising tungsten or molybdenum by exposing a substrate surface having at least one feature thereon sequentially to a metal precursor and a reducing agent comprising hydrogen to form the gap fill layer in the feature, wherein there is not a nucleation layer between the substrate surface and the gap fill layer.

TECHNICAL FIELD

The present disclosure relates generally to methods of depositing thinfilms. In particular, the disclosure relates to processes for thedeposition of gap fill films comprising, e.g., tungsten or molybdenum.

BACKGROUND

Manufacturing of 3D-NAND devices and devices for applications such aslogic and DRAM includes a process that can fill the word lines, vias,gaps, etc. with a metal. The presence of a metal in the word linesallows electrical connections to the control gates of NAND transistors.One challenge of such a metal fill is that, for example, the 3D-NANDstructures are microns deep. Another challenge is that the metal alsohas to fill the lateral spaces between the stacks of insulator (commonlysilicon oxide).

The deposition of gap fill thin films, e.g., tungsten- ormolybdenum-containing thin films, in features with ultra-high aspectratios is challenging. The 3D semiconductor devices require seamlessfill into horizontal and reentrant trenches. Incomplete trench fillingmay lead to high resistance, contamination, loss of filled materials,and, therefore, degradation of device performance.

Conventionally, the atomic layer deposition (ALD) of tungsten-containingmaterials are based on the binary reaction WF₆+3H₂→W+6HF. Briefly, WF6and H2 are exposed to substrate surface alternatingly (sequentially). Itis believed that WF6 partially decomposes on the substrate surface in aself-limiting reaction to form a fluorinated W surface with W-F exposed.An H₂ pulse reduces the fluorinated W-F surface to W. However, thereaction of WF₆ with the substrate (typically TiN) is very slow andexhibits significant incubation delay. This nucleation issue of WF₆ onthe substrate surface results in random surface growth and poordeposition conformality. Deposition of an interlayer on TiN beforeWF₆-H₂ ALD cycles can serve as a nucleation promotor. ALD ofmolybdenum-containing materials presents analogous chemistries andchallenges as the tungsten-containing materials.

Nucleation layers using metal silicides (WSix and MoSix) have been usedas way a to overcome the incubation delay issue on various surfacesincluding (Si, SiO₂, TiN, etc.). The metal silicides were deposited byALD using metal precursor and silanes (SiH₄, Si₂H₆, etc.) asco-reactant. However, silane-based metal silicide nucleation layer canexhibit high resistivity and high interfacial fluorine level.

There is a need in the art for methods of depositing a penetrating andconformal film to fill device components such as 3D-NAND word lines,vias and gaps for logic and DRAM and other applications. Additionally,there is a need in the art for methods of conformally and efficientlydepositing gap fill films comprising, e.g., tungsten or molybdenum.

SUMMARY

One or more embodiments of the disclosure are directed to processingmethods comprising forming a gap fill layer comprising tungsten ormolybdenum by exposing a substrate surface having at least one featurethereon sequentially to a metal precursor and a reducing agentcomprising hydrogen to form the gap fill layer in the feature. There isnot a nucleation layer between the substrate surface and the gap filllayer.

Additional embodiments of the disclosure are directed to processingmethods comprising positioning a substrate surface in a processingchamber. The substrate surface has at least one feature thereon. Thesubstrate surface is sequentially exposed to a first metal precursor anda reactant to form an underlying layer, wherein the first metalprecursor comprises one or more of a titanium precursor, an aluminumprecursor, and a silicon precursor, and the reactant comprises anitrogen precursor, an oxygen precursor, or combinations thereof. Theunderlying layer is sequentially exposed to a second metal precursorcomprising a tungsten precursor or a molybdenum precursor, and areducing agent comprising hydrogen (H₂) to form a gap fill layer on theunderlying layer.

Further embodiments of the disclosure are directed to processing methodscomprising placing a substrate having a substrate surface into aprocessing chamber comprising a plurality of sections. Each section isseparated from adjacent sections by a gas curtain. The substrate surfacehas at least one feature with a top, bottom and sides and an aspectratio of greater than or equal to 10:1. At least a portion of thesubstrate surface is exposed to a first process condition in a firstsection of the processing chamber. The first process condition comprisesa precursor of titanium, aluminum, silicon, or combinations thereof. Thesubstrate surface is laterally moved through a gas curtain to a secondsection of the processing chamber. The substrate surface is exposed to asecond process condition in the second section of the processingchamber. The second process condition comprises a reactant to form afilm with the precursor of titanium, aluminum, silicon or combinationsthereof, the film comprising TiN, TiN, TiON, TiSiN, TiSiON, AlN, TiAlN,or TiAlON. Exposure to the first and second sections, including lateralmovement of the substrate surface is optionally repeated to form anunderlying layer. The substrate surface is laterally moved through a gascurtain to a third section of the processing chamber. The substratesurface is exposed to a third process condition in the third section ofthe processing chamber. The third process condition comprises a tungstenprecursor or molybdenum precursor. The substrate surface is laterallymoved through a gas curtain to a fourth section of the processingchamber. The substrate surface is exposed to a fourth process conditionin the fourth section of the processing chamber. The fourth processcondition comprises hydrogen as a reductant to form a film with thetungsten or molybdenum precursor. Exposure to the third and fourthsections, including lateral movement of the substrate surface isoptionally repeated to fill the feature.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the above recited features of the presentdisclosure can be understood in detail, a more particular description ofthe disclosure, briefly summarized above, may be had by reference toembodiments, some of which are illustrated in the appended drawings. Itis to be noted, however, that the appended drawings illustrate onlytypical embodiments of this disclosure and are therefore not to beconsidered limiting of its scope, for the disclosure may admit to otherequally effective embodiments.

FIG. 1 shows a cross-sectional view of a batch processing chamber inaccordance with one or more embodiment of the disclosure;

FIG. 2 shows a partial perspective view of a batch processing chamber inaccordance with one or more embodiment of the disclosure;

FIG. 3 shows a schematic view of a batch processing chamber inaccordance with one or more embodiment of the disclosure;

FIG. 4 shows a schematic view of a portion of a wedge shaped gasdistribution assembly for use in a batch processing chamber inaccordance with one or more embodiment of the disclosure;

FIG. 5 shows a schematic view of a batch processing chamber inaccordance with one or more embodiments of the disclosure; and

FIG. 6 is a process flow diagram of a gap fill process in accordancewith one or more embodiments of the disclosure.

DETAILED DESCRIPTION

Before describing several exemplary embodiments of the invention, it isto be understood that the invention is not limited to the details ofconstruction or process steps set forth in the following description.The invention is capable of other embodiments and of being practiced orbeing carried out in various ways.

A “substrate” as used herein, refers to any substrate or materialsurface formed on a substrate upon which film processing is performedduring a fabrication process. For example, a substrate surface on whichprocessing can be performed include materials such as silicon, siliconoxide, strained silicon, silicon on insulator (SOI), carbon dopedsilicon oxides, amorphous silicon, doped silicon, germanium, galliumarsenide, glass, sapphire, and any other materials such as metals, metalnitrides, metal alloys, and other conductive materials, depending on theapplication. Substrates include, without limitation, semiconductorwafers. Substrates may be exposed to a pretreatment process to polish,etch, reduce, oxidize, hydroxylate, anneal and/or bake the substratesurface. In addition to film processing directly on the surface of thesubstrate itself, in the present invention, any of the film processingsteps disclosed may also be performed on an underlayer formed on thesubstrate as disclosed in more detail below, and the term “substratesurface” is intended to include such underlayer as the contextindicates. Thus for example, where a film/layer or partial film/layerhas been deposited onto a substrate surface, the exposed surface of thenewly deposited film/layer becomes the substrate surface.

According to one or more embodiments, the method uses an atomic layerdeposition (ALD) process. In such embodiments, the substrate surface isexposed to the precursors (or reactive gases) sequentially orsubstantially sequentially. As used herein throughout the specification,“substantially sequentially” means that a majority of the duration of aprecursor exposure does not overlap with the exposure to a co-reagent,although there may be some overlap. As used in this specification andthe appended claims, the terms “precursor”, “reactant”, “reactive gas”and the like are used interchangeably to refer to any gaseous speciesthat can react with the substrate surface.

Atomic Layer Deposition (ALD) is a process in which a substrate issequentially exposed to a precursor and a reactant to deposit a film.ALD is a self-limiting process that allows for monolayer control of thedeposition process. The immense amount of surface area of 3DNANDstructures uses a high dose of precursor in each ALD cycle. Aninsufficient dose might lead to non-conformal deposition. A dose istypically expressed as partial pressure of precursor multiplied byexposure time (1 Langmuir or 1 L=1E-6 Torr-second). To obtain a certaindose, the substrate can be exposed for a long time at a low partialpressure or a short time at a high partial pressure. The product of timeand pressure in both cases are equal. A high dose of precursor might beused for surface saturation on deep, entrenched structures that have alarge surface area. While embodiments of the disclosure are presentedwith reference to 3DNAND structures, those skilled in the art willunderstand that the disclosure is not limited to 3DNAND devices.Embodiments of the disclosure can be used with other applications, forexample, logic and DRAM.

High doses present a challenge to time-based ALD (also referred to astemporal ALD or time-domain ALD). For temporal ALD, process time andpartial pressure are not independent of each other. Exposure time mightbe minimized to achieve high wafer throughput. To achieve a high dose ina short exposure, a high precursor partial pressure might be used. Theinterdependence between process time and partial pressure of temporalALD is a result of the fact that there is a purge step between the twoprecursor exposures (or precursor and reactant) to ensure or minimizeany gas phase mixing of the precursors.

Ramping of the partial pressure up from zero (zero during purge) to acertain high value during the exposure step takes time. Ramping of thepartial pressure down from some high value to zero during the purge stepalso takes time. As a result, the total process time when a high dose ofprecursor is needed is generally not short. Using low pressures meansfaster ramp up/down of partial pressure, but use a longer exposure timefor a high dose. Using high pressure means slower ramp up/down ofpartial pressure although a short exposure suffices to achieve a highdose.

Spatial ALD does not have the fundamental interdependence betweenprocess time and partial pressure. For spatial ALD, precursor cycles arespatially separated. Each spatially-separated zone (process region) canmaintain pressure without any ramp up/down. A short exposure at highpressure for spatial ALD may be possible. The length of precursorexposure depends on how fast the substrate can be moved into and out ofeach spatially separated zone. Therefore, it is believed that spatialALD can achieve much higher wafer throughput than temporal ALD when highdose precursor processes are used.

One or more embodiments of the disclosure deposit a gap fill layer,e.g., W ALD or Mo ALD process, without a nucleation layer. Someembodiments of the disclosure provide methods that advantageously fillfeatures with aspect ratios of greater than 5:1, 10:1, 15:1, 20:1, 25:1,30:1, 35:1 or 40:1 with a film. Advantageously, such W ALD or Mo ALDprocess can be integrated with TiN ALD.

TiN and other Ti-, Al-, and Si-containing films are commonly under W orMo films on dielectric substrate. TiN is commonly used a glue layer forW films on dielectrice substrates. Applications include 3D-NANDwordline, DRAM buried wordline for 1x/y/z generation, source/draincontact and gate metal in CMOS for 10/7/5 nm technology node. Herein,detailed chemistries and processes will be presented with respect to W,but it is understood that the chemistries are analogous to Mo.Advantageously, hydrogen is used as the reductant rather thanhydrogen-containing compounds such as SiH₄ or B₂H₆ to achieve lowresistivity. Resistivity of films formed by SiH₄ or B₂H₆, for example,are much higher than H₂ reduced film.

Conventionally, the TiN layer and W layer were processed in differentchambers, and the TiN layer was exposed to air while inline waiting forW ALD process. Due to the surface oxidation of TiN layer, incubation ofthe W ALD process was delayed and deteriorated; thus a nucleation layerwas needed. One or more embodiments provide ways to reduce and/oreliminate surface oxidation of the so-called glue layer, which mayinclude but is not limited to: TiN, TiN, TiON, TiSiN, TiSiON, AlN,TiAlN, or TiAlON.

Some embodiments of the disclosure are directed to film depositionprocesses using a batch processing chamber, also referred to as aspatial processing chamber. FIG. 1 shows a cross-section of a processingchamber 100 including a gas distribution assembly 120, also referred toas injectors or an injector assembly, and a susceptor assembly 140. Thegas distribution assembly 120 is any type of gas delivery device used ina processing chamber. The gas distribution assembly 120 includes a frontsurface 121 which faces the susceptor assembly 140. The front surface121 can have any number or variety of openings to deliver a flow ofgases toward the susceptor assembly 140. The gas distribution assembly120 also includes an outer edge 124 which in the embodiments shown, issubstantially round.

The specific type of gas distribution assembly 120 used can varydepending on the particular process being used. Embodiments of thedisclosure can be used with any type of processing system where the gapbetween the susceptor and the gas distribution assembly is controlled.In a binary reaction, the plurality of gas channels can include at leastone first reactive gas A channel, at least one second reactive gas Bchannel, at least one purge gas P channel and/or at least one vacuum Vchannel. The gases flowing from the first reactive gas A channel(s), thesecond reactive gas B channel(s) and the purge gas P channel(s) aredirected toward the top surface of the wafer. Some of the gas flow moveshorizontally across the surface of the wafer and out of the processingregion through the purge gas P channel(s).

In some embodiments, the gas distribution assembly 120 is a rigidstationary body made of a single injector unit. In one or moreembodiments, the gas distribution assembly 120 is made up of a pluralityof individual sectors (e.g., injector units 122), as shown in FIG. 2.Either a single piece body or a multi-sector body can be used with thevarious embodiments of the disclosure described.

A susceptor assembly 140 is positioned beneath the gas distributionassembly 120. The susceptor assembly 140 includes a top surface 141 andat least one recess 142 in the top surface 141. The susceptor assembly140 also has a bottom surface 143 and an edge 144. The recess 142 can beany suitable shape and size depending on the shape and size of thesubstrates 60 being processed. In the embodiment shown in FIG. 1, therecess 142 has a flat bottom to support the bottom of the wafer;however, the bottom of the recess can vary. In some embodiments, therecess has step regions around the outer peripheral edge of the recesswhich are sized to support the outer peripheral edge of the wafer. Theamount of the outer peripheral edge of the wafer that is supported bythe steps can vary depending on, for example, the thickness of the waferand the presence of features already present on the back side of thewafer.

In some embodiments, as shown in FIG. 1, the recess 142 in the topsurface 141 of the susceptor assembly 140 is sized so that a substrate60 supported in the recess 142 has a top surface 61 substantiallycoplanar with the top surface 141 of the susceptor 140. As used in thisspecification and the appended claims, the term “substantially coplanar”means that the top surface of the wafer and the top surface of thesusceptor assembly are coplanar within ±0.2 mm. In some embodiments, thetop surfaces are coplanar within ±0.15 mm, ±0.10 mm or ±0.05 mm.

The susceptor assembly 140 of FIG. 1 includes a support post 160 whichis capable of lifting, lowering and rotating the susceptor assembly 140.The susceptor assembly may include a heater, or gas lines, or electricalcomponents within the center of the support post 160. The support post160 may be the primary means of increasing or decreasing the gap betweenthe susceptor assembly 140 and the gas distribution assembly 120, movingthe susceptor assembly 140 into proper position. The susceptor assembly140 may also include fine tuning actuators 162 which can makemicro-adjustments to susceptor assembly 140 to create a predeterminedgap 170 between the susceptor assembly 140 and the gas distributionassembly 120.

In some embodiments, the gap 170 distance is in the range of about 0.1mm to about 5.0 mm, or in the range of about 0.1 mm to about 3.0 mm, orin the range of about 0.1 mm to about 2.0 mm, or in the range of about0.2 mm to about 1.8 mm, or in the range of about 0.3 mm to about 1.7 mm,or in the range of about 0.4 mm to about 1.6 mm, or in the range ofabout 0.5 mm to about 1.5 mm, or in the range of about 0.6 mm to about1.4 mm, or in the range of about 0.7 mm to about 1.3 mm, or in the rangeof about 0.8 mm to about 1.2 mm, or in the range of about 0.9 mm toabout 1.1 mm, or about 1 mm.

The processing chamber 100 shown in the Figures is a carousel-typechamber in which the susceptor assembly 140 can hold a plurality ofsubstrates 60. As shown in FIG. 2, the gas distribution assembly 120 mayinclude a plurality of separate injector units 122, each injector unit122 being capable of depositing a film on the wafer, as the wafer ismoved beneath the injector unit. Two pie-shaped injector units 122 areshown positioned on approximately opposite sides of and above thesusceptor assembly 140. This number of injector units 122 is shown forillustrative purposes only. It will be understood that more or lessinjector units 122 can be included. In some embodiments, there are asufficient number of pie-shaped injector units 122 to form a shapeconforming to the shape of the susceptor assembly 140. In someembodiments, each of the individual pie-shaped injector units 122 may beindependently moved, removed and/or replaced without affecting any ofthe other injector units 122. For example, one segment may be raised topermit a robot to access the region between the susceptor assembly 140and gas distribution assembly 120 to load/unload substrates 60.

Processing chambers having multiple gas injectors can be used to processmultiple wafers simultaneously so that the wafers experience the sameprocess flow. For example, as shown in FIG. 3, the processing chamber100 has four gas injector assemblies and four substrates 60. At theoutset of processing, the substrates 60 can be positioned between theinjector assemblies 30. Rotating 17 the susceptor assembly 140 by 45°will result in each substrate 60 which is between gas distributionassemblies 120 to be moved to an gas distribution assembly 120 for filmdeposition, as illustrated by the dotted circle under the gasdistribution assemblies 120. An additional 45° rotation would move thesubstrates 60 away from the injector assemblies 30. The number ofsubstrates 60 and gas distribution assemblies 120 can be the same ordifferent. In some embodiments, there are the same numbers of wafersbeing processed as there are gas distribution assemblies. In one or moreembodiments, the number of wafers being processed are fraction of or aninteger multiple of the number of gas distribution assemblies. Forexample, if there are four gas distribution assemblies, there are 4xwafers being processed, where x is an integer value greater than orequal to one. In an exemplary embodiment, the gas distribution assembly120 includes eight processing regions separated by gas curtains and thesusceptor assembly 140 can hold six wafers.

The processing chamber 100 shown in FIG. 3 is merely representative ofone possible configuration and should not be taken as limiting the scopeof the disclosure. Here, the processing chamber 100 includes a pluralityof gas distribution assemblies 120. In the embodiment shown, there arefour gas distribution assemblies (also called injector assemblies 30)evenly spaced about the processing chamber 100. The processing chamber100 shown is octagonal; however, those skilled in the art willunderstand that this is one possible shape and should not be taken aslimiting the scope of the disclosure. The gas distribution assemblies120 shown are trapezoidal, but can be a single circular component ormade up of a plurality of pie-shaped segments, like that shown in FIG.2.

The embodiment shown in FIG. 3 includes a load lock chamber 180, or anauxiliary chamber like a buffer station. This chamber 180 is connectedto a side of the processing chamber 100 to allow, for example thesubstrates (also referred to as substrates 60) to be loaded/unloadedfrom the chamber 100. A wafer robot may be positioned in the chamber 180to move the substrate onto the susceptor.

Rotation of the carousel (e.g., the susceptor assembly 140) can becontinuous or intermittent (discontinuous). In continuous processing,the wafers are constantly rotating so that they are exposed to each ofthe injectors in turn. In discontinuous processing, the wafers can bemoved to the injector region and stopped, and then to the region 84between the injectors and stopped. For example, the carousel can rotateso that the wafers move from an inter-injector region across theinjector (or stop adjacent the injector) and on to the nextinter-injector region where the carousel can pause again. Pausingbetween the injectors may provide time for additional processing betweeneach layer deposition (e.g., exposure to plasma).

FIG. 4 shows a sector or portion of a gas distribution assembly 220,which may be referred to as an injector unit 122. The injector units 122can be used individually or in combination with other injector units.For example, as shown in FIG. 5, four of the injector units 122 of FIG.4 are combined to form a single gas distribution assembly 220. (Thelines separating the four injector units are not shown for clarity.)While the injector unit 122 of FIG. 4 has both a first reactive gas port125 and a second gas port 135 in addition to purge gas ports 155 andvacuum ports 145, an injector unit 122 does not need all of thesecomponents.

Referring to both FIGS. 4 and 5, a gas distribution assembly 220 inaccordance with one or more embodiment may comprise a plurality ofsectors (or injector units 122) with each sector being identical ordifferent. The gas distribution assembly 220 is positioned within theprocessing chamber and comprises a plurality of elongate gas ports 125,135, 155 and elongate vacuum ports 145 in a front surface 121 of the gasdistribution assembly 220. The plurality of elongate gas ports 125, 135,155 and elongate vacuum ports 145 extend from an area adjacent the innerperipheral edge 123 toward an area adjacent the outer peripheral edge124 of the gas distribution assembly 220. The plurality of gas portsshown include a first reactive gas port 125, a second gas port 135, avacuum port 145 which surrounds each of the first reactive gas ports andthe second reactive gas ports and a purge gas port 155.

With reference to the embodiments shown in FIG. 4 or 5, when statingthat the ports extend from at least about an inner peripheral region toat least about an outer peripheral region, however, the ports can extendmore than just radially from inner to outer regions. The ports canextend tangentially as vacuum port 145 surrounds reactive gas port 125and reactive gas port 135. In the embodiment shown in FIGS. 4 and 5, thewedge shaped reactive gas ports 125, 135 are surrounded on all edges,including adjacent the inner peripheral region and outer peripheralregion, by a vacuum port 145.

Referring to FIG. 4, as a substrate moves along path 127, each portionof the substrate surface is exposed to the various reactive gases. Tofollow the path 127, the substrate will be exposed to, or “see”, a purgegas port 155, a vacuum port 145, a first reactive gas port 125, a vacuumport 145, a purge gas port 155, a vacuum port 145, a second gas port 135and a vacuum port 145. Thus, at the end of the path 127 shown in FIG. 4,the substrate has been exposed to the first gas port 125 and the secondgas port 135 to form a layer. The injector unit 122 shown makes aquarter circle but could be larger or smaller. The gas distributionassembly 220 shown in FIG. 5 can be considered a combination of four ofthe injector units 122 of FIG. 4 connected in series.

The injector unit 122 of FIG. 4 shows a gas curtain 150 that separatesthe reactive gases. The term “gas curtain” is used to describe anycombination of gas flows or vacuum that separate reactive gases frommixing. The gas curtain 150 shown in FIG. 4 comprises the portion of thevacuum port 145 next to the first reactive gas port 125, the purge gasport 155 in the middle and a portion of the vacuum port 145 next to thesecond gas port 135. This combination of gas flow and vacuum can be usedto prevent or minimize gas phase reactions of the first reactive gas andthe second reactive gas.

Referring to FIG. 5, the combination of gas flows and vacuum from thegas distribution assembly 220 form a separation into a plurality ofprocessing regions 250. The processing regions are roughly definedaround the individual gas ports 125, 135 with the gas curtain 150between 250. The embodiment shown in FIG. 5 makes up eight separateprocessing regions 250 with eight separate gas curtains 150 between. Aprocessing chamber can have at least two processing region. In someembodiments, there are at least three, four, five, six, seven, eight,nine, 10, 11 or 12 processing regions.

During processing a substrate may be exposed to more than one processingregion 250 at any given time. However, the portions that are exposed tothe different processing regions will have a gas curtain separating thetwo. For example, if the leading edge of a substrate enters a processingregion including the second gas port 135, a middle portion of thesubstrate will be under a gas curtain 150 and the trailing edge of thesubstrate will be in a processing region including the first reactivegas port 125.

A factory interface 280, which can be, for example, a load lock chamber,is shown connected to the processing chamber 100. A substrate 60 isshown superimposed over the gas distribution assembly 220 to provide aframe of reference. The substrate 60 may often sit on a susceptorassembly to be held near the front surface 121 of the gas distributionassembly 120. The substrate 60 is loaded via the factory interface 280into the processing chamber 100 onto a substrate support or susceptorassembly (see FIG. 3). The substrate 60 can be shown positioned within aprocessing region because the substrate is located adjacent the firstreactive gas port 125 and between two gas curtains 150 a, 150 b.Rotating the substrate 60 along path 127 will move the substratecounter-clockwise around the processing chamber 100. Thus, the substrate60 will be exposed to the first processing region 250 a through theeighth processing region 250 h, including all processing regionsbetween.

Embodiments of the disclosure are directed to processing methodscomprising a processing chamber 100 with a plurality of processingregions 250 a-250 h with each processing region separated from anadjacent region by a gas curtain 150. For example, the processingchamber shown in FIG. 5. The number of gas curtains and processingregions within the processing chamber can be any suitable numberdepending on the arrangement of gas flows. The embodiment shown in FIG.5 has eight gas curtains 150 and eight processing regions 250 a-250 h.The number of gas curtains is generally equal to or greater than thenumber of processing regions.

A plurality of substrates 60 are positioned on a substrate support, forexample, the susceptor assembly 140 shown FIGS. 1 and 2. The pluralityof substrates 60 are rotated around the processing regions forprocessing. Generally, the gas curtains 150 are engaged (gas flowing andvacuum on) throughout processing including periods when no reactive gasis flowing into the chamber.

A first reactive gas A is flowed into one or more of the processingregions 250 while an inert gas is flowed into any processing region 250which does not have a first reactive gas A flowing into it. For exampleif the first reactive gas is flowing into processing regions 250 bthrough processing region 250 h, an inert gas would be flowing intoprocessing region 250 a. The inert gas can be flowed through the firstreactive gas port 125 or the second gas port 135.

The inert gas flow within the processing regions can be constant orvaried. In some embodiments, the reactive gas is co-flowed with an inertgas. The inert gas will act as a carrier and diluent. Since the amountof reactive gas, relative to the carrier gas, is small, co-flowing maymake balancing the gas pressures between the processing regions easierby decreasing the differences in pressure between adjacent regions.

FIG. 6 is a process flow diagram of a gap fill process 300 in accordancewith one or more embodiments of the disclosure. A substrate with a Ti-,Al-, and Si-containing surface, e.g., TiN, by ALD is provided in a firstchamber of a processing system at 310. In one or more embodiments, thefirst chamber may be where the TiN was formed.

In an ex situ embodiment, after TiN formation, the substrate may beexposed to air 320 during, for example, transfer to a second (separate)chamber. Due to the exposure to air, the surface may be exposed to achemical treatment at 340 to remove oxides. In the same (second)chamber, the surface may then be exposed to gap fill ALD 350 to apply Wor Mo using hydrogen as the reductant.

In an in situ embodiment, after TiN formation, the substrate is notexposed to air 330. This may occur when the substrate remains in thefirst chamber. For this embodiment, the surface may optionally beexposed to a chemical treatment at 360. In the same (first) chamber, thesurface may then be exposed to gap fill ALD 370 to apply W or Mo usinghydrogen as the reductant.

In some embodiments, the gap fill is a continuous film. As used herein,the term “continuous” refers to a layer that covers an entire exposedsurface without gaps or bare spots that reveal material underlying thedeposited layer. A continuous layer may have gaps or bare spots with asurface area less than about 1% of the total surface area of the film.

The Ti-, Al-, and Si- containing (e.g., TiN) ALD process can be temporalor spatial. Typical wafer temperature is in the range of 50° C. to 700°C., in the range of about 200° C. to about 500° C., or in the range ofabout 250° C. to about 450° C. Process pressure may be in the range of0.01 to 100 Torr. A co-reactant may comprise an oxygen source or anitrogen source. The co-reactant may be selected from the groupconsisting of: O₂, O₂ plasma, NO, NO plasma, N₂O, N₂O plasma, H₂O, H₂Oplasma, D₂O, O₃, NH₃, NH₃ plasma, N₂, N₂ plasma, H₂, H₂ plasma, andcombinations thereof. Inert gases (for example He, Ar, and the like) maybe present for dilution purposes.

Suitable titanium precursors include but are not limited to: TiCl₄,Til₄, or Ti[NMe_(2]4); a co-reactant to form TiN may be NH₃. Suitablesilicon precursors include, but are not limited to, poly-silanes(Si_(x)H_(y)) and organo-silanes. For example, poly-silanes includedisilane (Si₂H₆), trisilane (Si₃H₈), tetrasilane (Si₄H₁₀),isotetrasilane, neopentasilane (Si₅H₁₂), cyclopentasilane (Si₅H₁₀),hexasilane (Si₆H₁₄), cyclohexasilane (Si₆H₁₂) or, in general,Si_(x)H_(y) with x=2 or more and y=2x or 2x+2, and combinations thereof.Other silicon precursors may be DCS (SiH₂Cl₂), HMDS (Cl₃Si—SiCl₃), TSA(N(SiH₃)₃). Suitable aluminum precursors include, but are not limitedto, AlR₃, where R=is any ligand bonded to the Al by C, N, O, H, S, orhalide. For example, an aluminum precursor may comprise one or more ofthe following: an alkyl-containing aluminum compound, an aluminumalkoxide-based compound, an aluminum amino-based compound, an aluminumhalide, or combinations thereof. In an embodiment, the aluminumprecursor is trimethylaluminum (TMA) (AlMe₃). In an embodiment, thealuminum precursor is aluminum trichloride (AlCl₃) or aluminumtribromide (AlBr₃).

The chemical treatment in the gap fill ALD chamber occurs at a wafertemperature in the range of 50° C. to 700° C., in the range of about200° C. to about 500 ° C., or in the range of about 250° C. to about450° C. Process pressure may be in the range of 0.01 to 100 Torr.Chemical treatment to remove oxides include exposure of the substrate toone or more of the following: Si_(x)H_(2x+2), wherein x>=1;Si_(x)H_(y)F_(z), wherein x>=2 and y+z=2x+2; Si_(x)H_(y)Cl_(z), whereinx>=2 and y+z=2x+2; B_(x)H_(y), wherein x>=2 and y<=2x+2;B_(x)H_(y)Cl_(z), wherein x>=2 and y+z<=2x+2; B_(x)H_(y)F_(z), whereinx>=2 and y+z<=2x+2; and B_(x)H_(y)R_(z), wherein x>=2, y+z<=2x+2, and Rcomprises an alkyl group having 1 to 6 carbons.

Metal ALD Process. Tungsten or Molybdenum ALD process can be temporal orspatial. Typical wafer temperature is in the range of 50° C. to 700° C.,in the range of about 200° C. to about 500° C., or in the range of about250° C. to about 450° C. Process pressure may be in the range of 0.01 to100 Torr. Precursors may be WF₆, WCl₆, WCl₅, W(CO)₅, MoF₆, MoCl₆, MoCl₅;co-reactant is H₂. Inert gases including Ar, He, N₂ can be added intochamber.

Accordingly, one or more embodiments of the disclosure are directed toprocessing methods utilizing a batch processing chamber like that shownin FIG. 5. A substrate 60 is placed into the processing chamber whichhas a plurality of sections 250, each section separated from adjacentsection by a gas curtain 150. At least a portion of the substratesurface is exposed to a first process condition in a first section 250 aof the processing chamber. The first process condition of someembodiments comprises an aluminum-containing precursor.

The substrate surface is laterally moved through a gas curtain 150 to asecond section 250 b of the processing chamber. The substrate surface isexposed to a second process condition in the second section 250 b. Thesecond process condition of some embodiments comprises a reactant toform a film with the aluminum-containing precursor represented byAlC_(x)O_(y)N_(z), wherein x, y, and z are independently in the range of0-1.

The substrate surface is laterally moved through a gas curtain 150 to athird section 250 c of the processing chamber. The substrate surface canthen be exposed to a third process condition in the third section 250 c.The third process condition of some embodiments comprises a fluorinatingagent that reacts with the AlC_(x)O_(y)N_(z) film to form AlF₃.

The substrate surface is laterally moved through a gas curtain 150 to afourth section 250 d of the processing chamber. The substrate surfacecan then be exposed to a fourth process condition in the fourth section250 d. The fourth process condition of some embodiments comprises anetchant that reacts with the AlF₃ to make volatile species for removal.

In some embodiments, the substrate is exposed to additional first andsecond process conditions to form a film with a predetermined filmthickness. In some embodiments, the substrate is exposed to additionalthird and fourth process conditions to repeated etch the substratesurface.

Optionally, the substrate surface is laterally moved through a gascurtain 150 to a fifth section 250 e of the processing chamber. Thesubstrate surface can then be exposed to a fifth process condition inthe fifth section 250 e. The fifth process condition of some embodimentscomprises an oxidizing agent that reacts with Al—F bonds to make Al—Obonds.

According to one or more embodiments, the substrate is subjected toprocessing prior to and/or after forming the layer. This processing canbe performed in the same chamber or in one or more separate processingchambers. In some embodiments, the substrate is moved from the firstchamber to a separate, second chamber for further processing. Thesubstrate can be moved directly from the first chamber to the separateprocessing chamber, or it can be moved from the first chamber to one ormore transfer chambers, and then moved to the separate processingchamber. Accordingly, the processing apparatus may comprise multiplechambers in communication with a transfer station. An apparatus of thissort may be referred to as a “cluster tool” or “clustered system,” andthe like.

Generally, a cluster tool is a modular system comprising multiplechambers which perform various functions including substratecenter-finding and orientation, degassing, annealing, deposition and/oretching. According to one or more embodiments, a cluster tool includesat least a first chamber and a central transfer chamber. The centraltransfer chamber may house a robot that can shuttle substrates betweenand among processing chambers and load lock chambers. The transferchamber is typically maintained at a vacuum condition and provides anintermediate stage for shuttling substrates from one chamber to anotherand/or to a load lock chamber positioned at a front end of the clustertool. Two well-known cluster tools which may be adapted for the presentdisclosure are the Centura® and the Endura®, both available from AppliedMaterials, Inc., of Santa Clara, Calif. However, the exact arrangementand combination of chambers may be altered for purposes of performingspecific steps of a process as described herein. Other processingchambers which may be used include, but are not limited to, cyclicallayer deposition (CLD), atomic layer deposition (ALD), chemical vapordeposition (CVD), physical vapor deposition (PVD), etch, pre-clean,chemical clean, thermal treatment such as RTP, plasma nitridation,degas, orientation, hydroxylation and other substrate processes. Bycarrying out processes in a chamber on a cluster tool, surfacecontamination of the substrate with atmospheric impurities can beavoided without oxidation prior to depositing a subsequent film.

According to one or more embodiments, the substrate is continuouslyunder vacuum or “load lock” conditions, and is not exposed to ambientair when being moved from one chamber to the next. The transfer chambersare thus under vacuum and are “pumped down” under vacuum pressure. Inertgases may be present in the processing chambers or the transferchambers. In some embodiments, an inert gas is used as a purge gas toremove some or all of the reactants. According to one or moreembodiments, a purge gas is injected at the exit of the depositionchamber to prevent reactants from moving from the deposition chamber tothe transfer chamber and/or additional processing chamber. Thus, theflow of inert gas forms a curtain at the exit of the chamber.

The substrate can be processed in single substrate deposition chambers,where a single substrate is loaded, processed and unloaded beforeanother substrate is processed. The substrate can also be processed in acontinuous manner, similar to a conveyer system, in which multiplesubstrate are individually loaded into a first part of the chamber, movethrough the chamber and are unloaded from a second part of the chamber.The shape of the chamber and associated conveyer system can form astraight path or curved path. Additionally, the processing chamber maybe a carousel in which multiple substrates are moved about a centralaxis and are exposed to deposition, etch, annealing, cleaning, etc.processes throughout the carousel path.

During processing, the substrate can be heated or cooled. Such heatingor cooling can be accomplished by any suitable means including, but notlimited to, changing the temperature of the substrate support andflowing heated or cooled gases to the substrate surface. In someembodiments, the substrate support includes a heater/cooler which can becontrolled to change the substrate temperature conductively. In one ormore embodiments, the gases (either reactive gases or inert gases) beingemployed are heated or cooled to locally change the substratetemperature. In some embodiments, a heater/cooler is positioned withinthe chamber adjacent the substrate surface to convectively change thesubstrate temperature.

The substrate can also be stationary or rotated during processing. Arotating substrate can be rotated continuously or in discrete steps. Forexample, a substrate may be rotated throughout the entire process, orthe substrate can be rotated by a small amount between exposures todifferent reactive or purge gases. Rotating the substrate duringprocessing (either continuously or in steps) may help produce a moreuniform deposition or etch by minimizing the effect of, for example,local variability in gas flow geometries.

In atomic layer deposition type chambers, the substrate can be exposedto the first and second precursors either spatially or temporallyseparated processes. Temporal ALD is a traditional process in which thefirst precursor flows into the chamber to react with the surface. Thefirst precursor is purged from the chamber before flowing the secondprecursor. In spatial ALD, both the first and second precursors aresimultaneously flowed to the chamber but are separated spatially so thatthere is a region between the flows that prevents mixing of theprecursors. In spatial ALD, the substrate is moved relative to the gasdistribution plate, or vice-versa.

In embodiments, where one or more of the parts of the methods takesplace in one chamber, the process may be a spatial ALD process. Althoughone or more of the chemistries described above may not be compatible(i.e., result in reaction other than on the substrate surface and/ordeposit on the chamber), spatial separation ensures that the reagentsare not exposed to each in the gas phase. For example, temporal ALDinvolves the purging the deposition chamber. However, in practice it issometimes not possible to purge all of the excess reagent out of thechamber before flowing in additional regent. Therefore, any leftoverreagent in the chamber may react. With spatial separation, excessreagent does not need to be purged, and cross-contamination is limited.Furthermore, a lot of time can be taken to purge a chamber, andtherefore throughput can be increased by eliminating the purge step.

Reference throughout this specification to “one embodiment,” “certainembodiments,” “one or more embodiments” or “an embodiment” means that aparticular feature, structure, material, or characteristic described inconnection with the embodiment is included in at least one embodiment ofthe disclosure. Thus, the appearances of the phrases such as “in one ormore embodiments,” “in certain embodiments,” “in one embodiment” or “inan embodiment” in various places throughout this specification are notnecessarily referring to the same embodiment of the disclosure.Furthermore, the particular features, structures, materials, orcharacteristics may be combined in any suitable manner in one or moreembodiments.

Although the disclosure herein has been described with reference toparticular embodiments, it is to be understood that these embodimentsare merely illustrative of the principles and applications of thepresent disclosure. It will be apparent to those skilled in the art thatvarious modifications and variations can be made to the method andapparatus of the present disclosure without departing from the spiritand scope of the disclosure. Thus, it is intended that the presentdisclosure include modifications and variations that are within thescope of the appended claims and their equivalents.

1-15. (canceled)
 16. A processing method comprising: exposing asubstrate surface having at least one feature thereon to a chemicaltreatment to remove oxides and form a treated surface; and forming a gapfill layer comprising tungsten or molybdenum by sequentially exposingthe treated surface to a metal precursor and a reducing agent comprisinghydrogen to form the gap fill layer in the feature, wherein there is nota nucleation layer between the substrate surface and the gap fill layer.17. The processing method of claim 16, wherein the substrate surfacecomprises nitrides and/or oxides of titanium, aluminum, silicon, orcombinations thereof.
 18. The processing method of claim 17, wherein thesubstrate surface comprises TiN, TiON, TiSiN, TiSiON, AN, TiAlN, orTiAlON.
 19. The processing method of claim 16, wherein the metalprecursor is one or more of WF₆, WCl_(x), W(CO)₅, MoF₆, MoCl_(x), wherex is 5 or 6, and the reducing agent is H₂.
 20. The processing method ofclaim 16, wherein the treated surface is not exposed to air prior toforming the gap fill layer.
 21. The processing method of claim 16,wherein the chemical treatment comprises exposing the substrate surfaceto one or more of the following: Si_(x)H_(2x+2), wherein x>=1; SixHyFz,wherein x>=2 and y+z=2x+2; SixHyClz, wherein x>=2 and y+z=2x+2; BxHy,wherein x>=2 and y<=2x+2; BxHyClz, wherein x>=2 and y+z<=2x+2;B_(x)HyFz, wherein x>=2 and y+z<=2x+2; and B_(X)H_(y)R_(Z), whereinx>=2, y+z<=2x+2, and R comprises an alkyl group having 1 to 6 carbons.22. The processing method of claim 16, wherein the chemical treatmentexcludes the metal precursor.
 23. A processing method comprising:sequentially exposing a substrate surface having at least one featurethereon to a first metal precursor and a reactant to form an underlyinglayer, wherein the first metal precursor comprises one or more of atitanium precursor, an aluminum precursor, and a silicon precursor, andthe reactant comprises a nitrogen precursor, an oxygen precursor, orcombinations thereof; exposing the substrate surface to air and applyinga chemical treatment to the underlying layer to remove surface oxidationbefore forming a gap fill layer; and exposing the underlying layersequentially to a second metal precursor comprising a tungsten precursoror a molybdenum precursor, and a reducing agent comprising hydrogen (H₂)to form the gap fill layer on the underlying layer.
 24. The processingmethod of claim 23, wherein the reducing agent consists essentially ofhydrogen (H₂).
 25. The processing method of claim 23, wherein theunderlying layer comprises TiN, TiON, TiSiN, TiSiON, AN, TiAlN, orTiAlON.
 26. The processing method of claim 23, wherein the second metalprecursor is one or more of WF₆, WCl_(x), W(CO)₅, MoF₆, MoCl_(x), wherex is 5 or
 6. 27. The processing method of claim 23, wherein theunderlying layer is not exposed to air before forming the gap filllayer.
 28. The processing method of claim 23, further comprising beforeexposing the underlying layer sequentially to the second metal precursorand the hydrogen, exposing the substrate surface to air and applying achemical treatment to the underlying layer to remove surface oxidation.29. The processing method of claim 23, wherein the chemical treatmentcomprises exposing the substrate surface to one or more of thefollowing: Si_(x)H_(2x+2), wherein x>=1; SixHyFz, wherein x>=2 andy+z=2x+2; SixHyClz, wherein x>=2 and y+z=2x+2; BxHy, wherein x>=2 andy<=2x+2; BxHyClz, wherein x>=2 and y+z<=2x+2; BxHyFz, wherein x>=2 andy+z<=2x+2; and BxHyRz, wherein x>=2, y+z<=2x+2, and R comprises an alkylgroup having 1 to 6 carbons.
 30. The processing method of claim 23,wherein there is not a nucleation layer between the underlying layer andthe gap fill layer.